Job Complications Lead To AXIS System Solution

By Jeff Griffin, Senior Editor | January 2010 Vol. 65 No. 1

When Vermeer introduced the AXIS guided boring system earlier this year, it was presented as a new guided boring system capable of achieving pinpoint, on grade accuracy that eliminates many of the difficult procedures required by other underground installation methods.

The pit launched trenchless installation method often is described as similar to pilot tube boring, but with significant differences that set it apart from that process and other methods of trenchless construction. The AXIS system can maintain grades of less than 0.5 percent with pipes with diameters less than 24 inches (see box summarizing AXIS features).

Basic components of the system include power pack, rack, drill head, boring rod and vacuum and vacuum power pack and tank.

"At the beginning of the development process for the AXIS system, Vermeer established an 'A' team of engineering technicians designated for testing the system," said John Milligan, AXIS project manager. "As the product development process evolved, the team was expanded and has assumed responsibility for demonstrations with customers, machine start-ups and training."

One of the first projects in the U.S. completed with an AXIS system was the installation of a 160 foot on-grade segment of ductile iron sanitary sewer pipe in Kannapolis, NC. Project owner is the city of Kannapolis.

"The project was necessary to relocate a portion of a sewer line that went through school property and had to be moved because of construction at the school," said Stephen Bissinger, P.S., City of Kannapolis Public Works Department. "Although the sewer line is the property of the city's sewer infrastructure, the cost of the project was born by the school system."

Primary Contractor was Hendrick Construction, Charlotte, NC. Cherokee Construction, Indian Trail, NC, was the subcontractor for the street and intersection bore.

Abundant challenges
"This segment of the project called for 160 feet of 8 inch ductile iron pipe to be placed seven feet deep under a road and extending it into the major intersection across the street from a school," said Eric Mann, Cherokee Construction operations manager.

The work originally was specified as open cut; however, the city and department of transportation would not allow the intersection to be closed until a school holiday several months away.